1. Field of the Invention
The present invention relates to a display control device which outputs data exhibiting brightness of each pixel, to a display panel on which a plurality of pixels are arrayed, and in particular relates to frame rate control technology.
2. Description of the Related Art
A matrix-type display device such as a liquid crystal panel or the like, is configured by providing a plurality of pixels arrayed in a matrix form, and an image is displayed by the whole display device by making each pixel emit light at a desired brightness. Here, in order to make a pixel emit light, it is necessary to give an electrical signal, for example, voltage or current, corresponding to emitted light brightness, to the pixel. A driver circuit provides an electrical signal according to tone, to each pixel, based on an inputted m-bit multi-tone signal.
On the other hand, there are cases in which pixel data generated by computational processing means such as a graphics processor, a CPU (Central Processing Unit), or the like, are represented by a number of tones, m-bit, larger than n-bit that the driver circuit is capable of representing.
For example, a typical liquid crystal driver, used in a laptop personal computer or the like, receives a brightness signal of n=6-bit tones for each RGB (Red, Green, Blue) color, and drives pixels based on this. In contrast to this, there are cases in which image data is represented by m=8-bit tones for each color.
In such cases, in order to represent tones (2m) exceeding the number of tones (2n) that the driver circuit is capable of representing, technology known as frame rate control (referred to as FRC below) is used. In FRC a plurality of data, obtained by the upper n-bits being adjusted, in accordance with the lower (m-n) bits of brightness data, are generated, and the plurality of data undergoes time division to be outputted. In this way, even in cases in which an n-bit driver circuit is used, it is possible to represent brightness of pixels by approximately m-bit multi-tones in a simulated manner. For example, related technology is disclosed in Patent Document 1.    Patent Document 1: Japanese Patent Application, Laid Open No. H2003-302955
Using FRC, it is possible to represent more tones than 2n tones that a driver circuit is capable of representing. For example, in cases where m=8-bit and n=6-bit, if 4 frames are used to implement FRC, representation of 2n−3=253 tones is possible for each color, and 2533≈16,200,000 colors can be represented by a pixel. However, image data itself is represented by 8-bit 256 tones for each color, and since a pixel is represented by 2563≈16,770,000 colors, there is a problem in that about 600,000 colors cannot be represented.